A flexible sigmoidoscopy is a procedure that examines the rectum and lower colon, also called the sigmoid colon using a flexible tube. The flexible sigmoidoscope used by the doctor contains a light and a tiny camera at the end. The scoping instrument does not allow the doctor to see the as much of the colon as with a colonoscopy. Consequently the procedure is not preferred for the detection of cancer or polyps, but can be useful to look for causes of rectal bleeding or diarrhea.

The sigmoidoscopy procedure is conducted usually without sedation in the endoscopy center. Patients should not eat or drink prior to a sigmoidoscopy, and will need to take important steps to prepare for the procedure.